1. Field of the Invention
The present invention relates to data transmission by cellular telephone or other wireless communication channels, and particularly to an adaptive CQI-based HSDPA flow control method for providing high speed downlink packet access (HSDPA) control.
2. Description of the Related Art
High Speed Downlink Packet Access (HSDPA) is an incremental upgrade to 3G UMTS cellular systems that is optimized for asymmetric data traffic, such as web traffic, which dominates today's Internet. Since being released by 3GPP Release 5 in 2002, HSDPA has gained momentum as a true broadband mobile Internet technology, with downlink speeds ranging from 1.8, 3.6, up to 7.2 Mbps and even higher speeds with recent developments. HSDPA employs advanced mechanisms that provide significant capacity improvements over previous releases of 3G/UMTS systems. The principal element of this improvement is the time-multiplexing of users on a high speed shared channel using a fast scheduler located at the base station.
The most commonly used scheduling algorithm in HSDPA is the Proportional Fair (PF) scheduler, which tries to maximize the system capacity by exploiting the short term variations in channel quality in a relatively fair manner. To operate optimally, this algorithm requires that sufficient amount of traffic is always available in the user's buffer at the base station. However, the buffer levels at the base station are constrained by a flow control protocol that is defined over the Iub link in HSDPA to minimize data loss during handover.
Thus, an adaptive CQI-based HSDPA flow control method solving the aforementioned problems is desired.